Active Skid Control System (Asc) - Lancer Evolution: Other Mitsubishi Lancer X

MAIN COMPONENTS AND FUNCTIONS

MAIN COMPONENTS AND FUNCTIONS CHART

FAIL-SAFE FUNCTIONS

When a malfunction is determined by the diagnostic function, ASC-ECU illuminates the ABS warning light, ABS warning display, brake warning display, brake warning light *, ASC warning display, and ASC OFF display. At the same time, ASC-ECU prohibits the ABS, EBD, skid control, and TCL control.

Note. *: The brake warning light and brake warning display are used as the EBD control warning light.

Illumination condition of warning light and display in case of failure

DTC CHART - ILLUMINATION CONDITION OF WARNING LIGHT IN CASE OF FAILURE

EBD, ABS, skid control, and TCL control status at failure

DTC CHART - EBD, ABS, SKID CONTROL, AND TCL CONTROL STATUS AT FAILURE

PROBABLE CAUSES

1. Wheel bearing malfunction
2. Deformation of the magnetic encoder for wheel speed detection
3. Adhesion of foreign materials on the magnetic encoder for wheel speed detection
4. ABS-ECU malfunction
5. Disturbance of magnetization pattern for magnetic encoder for wheel speed detection
6. Missing teeth of the magnetic encoder for wheel speed detection

1. Wheel bearing malfunction
2. Deformation of the magnetic encoder for wheel speed detection
3. Adhesion of foreign materials on the magnetic encoder for wheel speed detection
4. ASC-ECU malfunction
5. Disturbance of magnetization pattern for magnetic encoder for wheel speed detection
6. Missing teeth of the magnetic encoder for wheel speed detection

1. Wheel bearing malfunction
2. Deformation of the magnetic encoder for wheel speed detection
3. Adhesion of foreign materials on the magnetic encoder for wheel speed detection
4. ABS-ECU malfunction
5. Disturbance of magnetization pattern for magnetic encoder for wheel speed detection
6. Missing teeth of the magnetic encoder for wheel speed detection

1. Wheel bearing malfunction
2. Deformation of the magnetic encoder for wheel speed detection
3. Adhesion of foreign materials on the magnetic encoder for wheel speed detection
4. ABS-ECU malfunction
5. Disturbance of magnetization pattern for magnetic encoder for wheel speed detection
6. Missing teeth of the magnetic encoder for wheel speed detection

1. Damaged wiring harness and connectors
2. External noise interference
3. Malfunction of wheel speed sensor
4. ABS-ECU malfunction
5. Excessive gap between the wheel speed sensor and the magnetic encoder for wheel speed detection
6. Adhesion of foreign materials on the wheel speed sensor
7. Adhesion of foreign materials on the magnetic encoder for wheel speed detection
8. Wheel bearing malfunction
9. Improper installation of the wheel speed sensor
10. Deformation of the magnetic encoder for wheel speed detection
11. Disturbance of magnetization pattern for magnetic encoder for wheel speed detection
12. Missing teeth of the magnetic encoder for wheel speed detection

1. Damaged wiring harness and connectors
2. External noise interference
3. Malfunction of wheel speed sensor
4. ABS-ECU malfunction
5. Excessive gap between the wheel speed sensor and the wheel speed detection encoder
6. Adhesion of foreign materials on the wheel speed sensor
7. Adhesion of foreign materials on the wheel speed detection encoder
8. Wheel bearing malfunction
9. Improper installation of the wheel speed sensor
10. Deformation of the wheel speed detection encoder
11. Disturbance of magnetization pattern for wheel speed detection encoder
12. Missing teeth of the wheel speed detection encoder

1. Damaged wiring harness and connectors
2. External noise interference
3. Malfunction of wheel speed sensor
4. ABS-ECU malfunction
5. Excessive gap between the wheel speed sensor and the wheel speed detection encoder
6. Adhesion of foreign materials on the wheel speed sensor
7. Adhesion of foreign materials on the wheel speed detection encoder
8. Wheel bearing malfunction
9. Improper installation of the wheel speed sensor
10. Deformation of the wheel speed detection encoder
11. Disturbance of magnetization pattern for wheel speed detection encoder
12. Missing teeth of the wheel speed detection encoder

1. Damaged wiring harness and connectors
2. External noise interference
3. Malfunction of wheel speed sensor
4. ABS-ECU malfunction
5. Excessive gap between the wheel speed sensor and the wheel speed detection encoder
6. Adhesion of foreign materials on the wheel speed sensor
7. Adhesion of foreign materials on the wheel speed detection encoder
8. Wheel bearing malfunction
9. Improper installation of the wheel speed sensor
10. Deformation of the wheel speed detection encoder
11. Disturbance of magnetization pattern for wheel speed detection encoder
12. Missing teeth of the wheel speed detection encoder

ASC-ECU malfunction

1. Incorrect brake pedal height
2. Incorrect adjustment of stoplight switch
3. Master cylinder malfunction
4. Brake booster malfunction
5. ASC-ECU malfunction

1. Incorrect adjustment of brake pedal height
2. Master cylinder malfunction
3. Brake booster malfunction
4. Incorrect installation position of stoplight switch
5. Malfunction of the stoplight switch
6. Brake drag
7. Malfunction of the ASC-ECU

1. Damaged wiring harness and connectors
2. Malfunction of hydraulic unit (with built-in wheel cylinder pressure sensor)

1. Damaged wiring harness and connectors
2. Incorrect adjustment of brake pedal height
3. Master cylinder malfunction
4. Brake booster malfunction
5. Incorrect installation position of stoplight switch
6. Malfunction of the stoplight switch
7. Brake drag
8. Malfunction of the ASC-ECU

1. Improper adjustment of stoplight switch installation position
2. Malfunction of the stoplight switch
3. Malfunction of the stoplight
4. Damaged wiring harness and connectors
5. Malfunction of ETACS-ECU
6. Malfunction of the ASC-ECU

1. Steering wheel sensor malfunction
2. G and yaw rate sensor malfunction
3. Improper installation of steering wheel sensor or G and yaw rate sensor
4. ASC-ECU malfunction
5. Different steering wheel
6. Wheel alignment not performed

ASC-ECU malfunction

1. Battery failure
2. Battery terminal looseness
3. Fusible link malfunction
4. Damaged wiring harness and connectors
5. ASC-ECU malfunction
6. Charging system failed

1. Different hydraulic unit (For delivery to factory)
2. ASC-ECU malfunction

1. Wrong coding
2. Engine ECU malfunction
3. ASC-ECU malfunction
4. External noise interference

1. Engine ECU malfunction
2. Malfunction of transaxle assembly < TC-SST >
3. S-AWC-ECU malfunction
4. ETACS-ECU malfunction
5. Steering wheel sensor malfunction
6. Malfunction of the CAN bus
7. ASC-ECU malfunction
8. Local CAN-bus line malfunction
9. Interchanging of ETACS-ECU with another vehicle

1. Malfunction of the CAN bus
2. Engine ECU malfunction
3. ASC-ECU malfunction
4. First ignition switch ON after replacement of ASC-ECU

1. ETACS-ECU or ASC-ECU which was equipped with other vehicle is used.
2. Malfunction of ETACS-ECU
3. ASC-ECU malfunction
4. External noise interference

1. G and yaw rate sensor malfunction
2. ASC-ECU malfunction
3. External noise interference
4. The G and yaw rate sensor for FWD is installed.

1. Improper installation of the G and yaw rate sensor
2. G and yaw rate sensor malfunction
3. Wheel speed sensor malfunction
4. ASC-ECU malfunction
5. External noise interference NOTE: This DTC may be set also when the vehicle is driven on the four-wheel drum tester.

1. Improper installation of the G and yaw rate sensor
2. G and yaw rate sensor malfunction
3. Steering wheel sensor malfunction
4. Improper installation of steering wheel sensor
5. Malfunction of wheel speed sensor
6. ASC-ECU malfunction
7. External noise interference

1. Improper installation of the G and yaw rate sensor
2. Damaged wiring harness and connectors
3. G and yaw rate sensor malfunction
4. ASC-ECU malfunction

ASC-ECU malfunction

1. Damaged wiring harness and connectors
2. G and yaw rate sensor malfunction
3. ASC-ECU malfunction

1. Accidental shutdown of power supply during storing operation of calibrated value
2. ASC-ECU malfunction
3. External noise interference

1. Improper installation of steering wheel sensor
2. Wheel alignment not performed
3. Steering wheel sensor malfunction
4. Different steering wheel
5. G and yaw rate sensor malfunction
6. Wheel speed sensor malfunction
7. ASC-ECU malfunction
8. External noise interference

1. Neutral position of steering wheel sensor not learned
2. Steering wheel sensor malfunction
3. ASC-ECU malfunction

1. Steering wheel sensor malfunction
2. ASC-ECU malfunction
3. External noise interference

1. Disconnection of the ASC-ECU connector or the battery terminal when the ignition switch is ON
2. Loose battery terminal
3. Abnormality in battery
4. Damaged wiring harness and connectors
5. ASC-ECU malfunction

1. ASC-ECU malfunction
2. Noise interference

1. Wiring harness or connector failure of CAN bus line
2. ASC-ECU malfunction
3. ECU malfunction of other system

1. Wiring harness or connector failure in special CAN bus lines (Local CAN) between ASC-ECU and G and yaw rate sensor.
2. G and yaw rate sensor malfunction
3. ASC-ECU malfunction
4. External noise interference

1. Malfunction of engine system
2. Engine ECU malfunction
3. ASC-ECU malfunction
4. External noise interference

1. Steering wheel sensor malfunction
2. ASC-ECU malfunction
3. External noise interference

1. Wiring harness or connector failure in special CAN bus lines (Local CAN) between ASC-ECU and S-AWC-ECU
2. S-AWC-ECU malfunction
3. ASC-ECU malfunction

1. Wiring harness or connector failure in special CAN bus lines between ASC-ECU and G and yaw rate sensor
2. G and yaw rate sensor malfunction
3. ASC-ECU malfunction

1. Variant coding for ETACS-ECU has not been implemented.
2. ASC-ECU malfunction

1. ETACS-ECU malfunction
2. Engine ECU malfunction
3. ETACS-ECUs have been interchanged between two vehicles.
4. ASC-ECU malfunction
5. Noise interference
6. ASC-ECUs have been interchanged between two vehicles.

1. Damaged wiring harness and connectors
2. ASC-ECU malfunction
3. Wrong M.U.T.-III wiring harness
4. Abnormality in battery or generator
5. Abnormality in power supply voltage to ASC-ECU
6. ECU malfunction of other system

1. The brake pad thickness is at the limit value or less.
2. The brake fluid amount is at the "LOWER" level or lower.
3. Poor adjustment of the parking brake lever
4. Damaged wiring harness and connectors
5. Parking brake switch malfunction
6. Brake fluid level switch malfunction
7. Combination meter malfunction
8. ETACS-ECU malfunction

1. Damaged harness wires and connectors
2. Malfunction of the ETACS-ECU
3. Malfunction of the combination meter
4. Malfunction of ASC-ECU
5. Abnormality with ETACS-ECU coding data

1. Damaged wiring harness and connectors
2. Malfunction of ETACS-ECU
3. Combination meter malfunction
4. ASC-ECU malfunction

1. Damaged wiring harness and connectors
2. Malfunction of ETACS-ECU
3. Combination meter malfunction
4. ASC-ECU malfunction
5. Control stop due to the low voltage NOTE: Due to the abnormality in the supply voltage, the diagnostic trouble code may not be set even when the ABS warning light is illuminated.

1. Damaged wiring harness and connectors
2. Malfunction of ETACS-ECU
3. Combination meter malfunction
4. ASC-ECU malfunction
5. Control stop due to the low voltage NOTE: Due to the abnormality in the supply voltage, the diagnostic trouble code may not be set even when the ASC warning display is illuminated.

1. Damaged wiring harness and connectors
2. ASC OFF switch malfunction
3. ETACS-ECU malfunction
4. Combination meter malfunction
5. ASC-ECU malfunction

1. Damaged wiring harness and connectors
2. ASC OFF switch malfunction
3. ETACS-ECU malfunction
4. Combination meter malfunction

1. Malfunction of hydraulic unit (integrated with ABS-ECU)
2. Malfunction of hydraulic circuit
3. Malfunction of brake assembly
4. Malfunction of brake booster
5. Malfunction of master cylinder assembly

1. Low battery output
2. Wiring harness or connector failure of CAN bus line
3. ASC-ECU malfunction
4. Different ETACS-ECU, abnormal variant coding information
5. Abnormal engine coding data

1. Damaged wiring harness and connectors
2. Malfunction of fuse or fusible link
3. Improper tightening of battery terminal
4. Improper tightening of grounding bolt
5. Battery failure
6. Charging system failed
7. ASC-ECU malfunction

1. Installation of wheel or tire other than genuine specified size
2. Tire pressure abnormality
3. Tire wear and deterioration
4. Installation of non-genuine braking device or non-genuine impact reducing device
5. Wheel alignment abnormality
6. Malfunction of brake-related components
7. Malfunction of wheel speed sensor
8. Malfunction of G and yaw rate sensor
9. Malfunction of steering wheel sensor
10. Malfunction of hydraulic unit (integrated with ASC-ECU)
11. Malfunction of hydraulic circuit
12. External noise interference

DATA LIST REFERENCE TABLE

The following items of ECU input data can be read using the scan tool.

1. The system is normal. DATA LIST REFERENCE Item No. Check item Check conditions Normal conditions 01 FL wheel speed sensor Perform a test run of the vehicle. The speedometer display and scan tool display almost agree with each other. < Vehicle stopped: Approximately 0.7 km/h (1.1 mph) > 02 FR wheel speed sensor 03 RL wheel speed sensor 04 RR wheel speed sensor 05 Power supply voltage System voltage (10 to 18 V ASC operable range) 07 Brake switch (input) The brake pedal is depressed. ON The brake pedal is released. OFF 08 Lateral G sensor (+: left turn, -: right turn) Vehicle stopped (level) -0.11 to 0.11 G Running -1 to 1 G 09 G sensor (+: deceleration, -: acceleration) Vehicle stopped (level) -0.11 to 0.11 G Running -1 to 1 G 10 Master cylinder pressure The brake pedal is depressed. Increases by the amount of the brake pedal depression. The brake pedal is released. -3 to 3 bar 11 Steering angle (+: left turn, -: right turn) Vehicle stopped (Steering wheel in neutral position) -6 to 6 deg Running Nearly the same as the steering wheel operation angle <-720 to 720 deg (ASC-ECU normal detection value)> When removed from vehicle (Steering wheel sensor as a single unit) Nearly the same as the steering wheel operation angle <-850 to 850 deg (Sensor normal value as a single unit)> 12 Yaw rate sensor (+: left turn, -: right turn) Vehicle stopped (level) -3.6 to 3.6 deg/s Running -100 to 100 deg/s 14 Brake switch The brake pedal is depressed. ON The brake pedal is released. OFF 15 Emission test mode Emission test mode: ON ON Emission test mode: OFF OFF 26 Brake fluid pressure switch Brake fluid level is lower than the "LOWER" marking. Low Brake fluid level is higher than the "LOWER" marking. Normal 28 ASC/TCL off switch ASC OFF switch not operated (ASC control is available) ON When ASC OFF switch is operated (pressed shortly) (ASC control is prohibited) OFF When ASC OFF switch is operated (pressed and held for 15 seconds or more) (ASC OFF control is prohibited by fail-safe.) ON 45 SAS OK flag When the learning is completed Comp When the learning is not completed Not Comp When the steering wheel sensor is faulty SAS fail SAS fail&Not Comp 65 Engine Speed When the accelerator pedal is depressed (engine started) The tachometer display and the scan tool display almost agree with each other. 66 Engine torque Displays the engine torque. 67 APS sensor Displays the accelerator pedal opening angle. 68 Allow ESP torque request Engine torque intervention is permitted Allow 70 Target gear The shift lever is operated Displays the shift lever position. 71 Actual gear 72 Master cylinder pressure Offset Master cylinder pressure sensor correction amount at the master cylinder pressure sensor calibration -8 to 8 bar 73 Lateral G sensor offset Lateral G sensor correction amount at G and yaw rate sensor calibration -0.17 to 0.17 G 86 Ignition switch Ignition switch is "ON" position ON 87 Ignition switch (input) Ignition switch is "ON" position ON Ignition switch is "START" position START 88 Vehicle speed Perform a test run of the vehicle. The speedometer display and scan tool display almost agree with each other. 91 Brake pressure sensor The brake pedal is depressed. Pressed The brake pedal is released. Not pressed 96 G sensor offset Longitudinal G sensor correction amount at G and yaw rate sensor calibration -0.3 to 0.3 G 97 Yaw rate sensor offset Yaw rate sensor correction amount at G and yaw rate sensor calibration -6.0 to 6.0 deg/s 105 Power supply voltage (input) System voltage (10 to 18 V ASC operable range) 120 Parking brake switch (input) When the parking brake lever is pulled up. ON When the parking brake lever is released. OFF 128 ASC/TCL off switch When the ASC OFF switch is pressed. ON When the ASC OFF switch is not pressed. OFF 129 FL wheel cylinder pressure The brake pedal is depressed. Increases by the amount of the brake pedal depression. The brake pedal is released. -3 to 3 bar 130 FR wheel cylinder pressure The brake pedal is depressed. Increases by the amount of the brake pedal depression. The brake pedal is released. -3 to 3 bar 131 RL wheel cylinder pressure The brake pedal is depressed. Increases by the amount of the brake pedal depression. The brake pedal is released. -3 to 3 bar 132 RR wheel cylinder pressure The brake pedal is depressed. Increases by the amount of the brake pedal depression. The brake pedal is released. -3 to 3 bar 133 FL wheel cylinder pres. offset Wheel cylinder fluid pressure sensor correction amount -8 to 8 bar 134 FR wheel cylinder pres. offset 135 RL wheel cylinder pres. offset 136 RR wheel cylinder pres. offset
2. System shutdown by ECU While ASC-ECU is disabled by the diagnostic function, the scan tool displayed data is different from the actual measurement.

TERMINAL VOLTAGE CHECK

Required Special Tool

MB991997: ASC Check Harness

Scheme 56

Scheme 57

1. Operate the lock lever as shown in the+ figure to disconnect the ASC-ECU wiring harness connector.
2. Connect special tool ASC Check Harness (MB991997) to measure the voltage between each check connector terminal and the ground terminal (No. 16 or 47).

VOLTAGE SPECIFICATIONS

HYDRAULIC UNIT CHECK

Required Special Tools

1. MB991958: M.U.T.-III Sub Assembly MB991824: Vehicle Communication Interface (V.C.I.) MB991827: M.U.T.-III USB Cable MB991910: M.U.T.-III Main Harness A (Vehicles with CAN communication system)

Scheme 58

1. Raise the vehicle using a jack and support the specified points with a rigid rack. CAUTION: Before connecting or disconnecting scan tool, always turn the ignition switch to the LOCK (OFF) position.
2. Before setting scan tool, turn the ignition key to the LOCK (OFF) position.
3. With the M/T vehicles, check that the shift lever is in the neutral position. With the TC-SST vehicle, check that the selector lever is in the "N" position. Then, start the engine of the vehicle.
4. When carrying out the actuator tests No. 01 to 04, perform the actuator tests using scan tool while depressing the brake pedal. When carrying out the actuator tests No.05 to 08, perform the actuator tests using scan tool without depressing the brake pedal. When carrying out the actuator tests, rotate the wheel by hands to confirm that the braking force changes. NOTE: While performing the actuator test, the ABS warning light flashes at a rate of 2 Hz. When ASC-ECU is disabled due to the fail-safe function, the M.U.T.-III actuator test cannot be performed. After the actuator test has been performed, the ABS warning light, brake warning light, ASC warning display, and ASC OFF indicator light illuminate until the ignition switch is turned to ON again or the communication between scan tool and ASC-ECU is terminated.
5. This is indicated as shown in the above.
6. When any malfunction has been found, take a necessary action according to the "Judgment Table". JUDGMENT CHART Display on scan tool Operation Inspection result Judgment Probable cause Remedy 01 FL wheel ABS drive 02 FR wheel ABS drive 03 RL wheel ABS drive 04 RR wheel ABS drive Depress the brake pedal to lock the vehicle. Select the vehicle to be inspected using scan tool, perform the actuator test. Rotate the selected wheel by hands to confirm the braking force. Braking force decreases for 3 seconds from the lock status. Normal - - The wheel does not lock even if the brake pedal is depressed. Error Clogged brake line other than hydraulic unit Check and clean the brake line. Clogged hydraulic circuit in the hydraulic unit Replace the hydraulic unit assembly. Braking force does not decrease. Faulty routing of hydraulic unit brake tube Route the brake tube correctly. Malfunction of hydraulic unit solenoid valve operation Replace the hydraulic unit assembly. 05 FL wheel TCL drive 06 FR wheel TCL drive 07 RL wheel TCL drive 08 RR wheel TCL drive Select the vehicle to be inspected using scan tool, perform the actuator test. Rotate the selected wheel by hands to confirm the braking force. Lock condition occurs for 3 seconds from the status without braking force. Normal - - The wheel does not lock. Error Faulty routing of hydraulic unit brake tube Clogged brake line other than hydraulic unit Check and clean the brake line. Clogged hydraulic circuit in the hydraulic unit Replace the hydraulic unit assembly.
7. After the inspection, turn the ignition switch to the LOCK (OFF) position, and then disconnect scan tool.

IN THE EVENT OF A DISCHARGED BATTERY

If the engine is started using a booster cable when the battery is completely flat, and the vehicle is then driven without waiting for the battery to be recharged, the engine may misfire and it may not be possible to drive the vehicle. This is because the ASC consumes a large amount of current when carrying out its initial checks. If this happens, recharge the battery fully.

>> A << BRAKE TUBE CONNECTION

Install the brake pipe to the hydraulic unit as shown in the figure.

Scheme 59

1. From master cylinder (primary)
2. To front brake (RH)
3. To front brake (LH)
4. From master cylinder (secondary)
5. To rear brake (RH)
6. To rear brake (LH)

WHEEL SPEED SENSOR CURRENT CHECK

Scheme 60

1. Connect the circuit tester to the wheel speed sensor using the special tool extra fine probe (MB992006), and measure the sensor current as a single unit. Standard value: 5.9 to 8.4 mA or 11.8 to 16.8 mA
2. If the measurement value is not within the standard value range, replace the wheel speed sensor with a new one.

Scheme 61

1. Connect the circuit tester to the wheel speed sensor using the special tool extra fine probe (MB992006), and measure the insulation resistance between terminal No. 1/2 and the wheel speed sensor body as a single unit. Standard value: 5 Mohms or more
2. If the insulation resistance is not within the standard value range, replace the wheel speed sensor with a new one.

>> A << NEUTRAL POSITIONING OF STEERING WHEEL SENSOR

Scheme 62

Scheme 63

1. Align the mating marks of the clock spring. < Alignment of mating marks > Turn the clock spring clockwise fully. Turn the clock spring counterclockwise approximately three and 3/4 turns to align the mating marks. Check that the white roller is visible from the window for checking the neutral point with the mating marks being aligned. NOTE: If the white roller is invisible, the neutral point is not aligned correctly. CAUTION: Always align three mating marks of the steering wheel sensor simultaneously as shown in the figure. If these mating marks are not aligned correctly, the steering wheel sensor may be damaged.
2. Align three mating marks of the steering wheel sensor simultaneously as shown in the figure. < Alignment of mating marks > Check the window for inspecting the neutral position of the steering wheel sensor. If the mating marks cannot be seen from the window, align the mating marks as shown in the figure. Install the steering wheel sensor to the column switch assembly, maintaining the neutral position correctly. NOTE: A new steering wheel sensor has a lock clip for preventing the rotation of (fixing) the steering wheel sensor. After installing the column switch assembly, remove this lock clip. Install the column switch assembly to the vehicle, maintaining the neutral position correctly.